Tamoxifen in Treating Women With High-Risk Breast Cancer

DISEASE CHARACTERISTICS: Adenocarcinoma of the breast with 1 or more histologically proven positive axillary nodes OR Adenocarcinoma of the breast with negative axillary nodes or adverse prognostic factors such that the patient is at high risk for recurrence and node negative lesion is characterized by the following features: Tumor at least 1 cm Poorly differentiated, SBR grade III, or MSBR grade V and/or lymphatic/vascular invasion Pathologic review by experienced breast pathologist recommended if grade is unspecified and lymphatic/vascular invasion is absent Disease considered potentially curable and treated by 1 of the following: Complete surgical removal of the breast plus axillary node dissection Partial surgical removal of the breast plus axillary node dissection, with the intention of giving breast irradiation following completion of an adjuvant chemotherapy regimen Regional nodal or chest wall irradiation not prohibited but strongly discouraged No evidence of residual tumor in the axilla following dissection No microscopic evidence of residual tumor at the resection margins following total mastectomy Further excision highly recommended if there is microscopic residual disease present at partial mastectomy margins If further excision is not undertaken, a radiotherapy boost to the tumor bed is required in addition to breast irradiation given following protocol chemotherapy Disease clinically staged prior to surgery as T1-T3a, N0-2, M0 No clinical T4 disease, i.e.: No extension to the chest wall No edema (including peau d'orange) No skin ulceration No satellite skin nodules confined to the same breast No inflammatory carcinoma Disease pathologically staged following surgery as TNM stage I, II, or III (T0-4; N0-2; M0) T4 allowed only with dermal involvement on pathology assessment No evidence of metastatic disease beyond the homolateral axillary nodes on pre-chemotherapy chest x-ray, bone scan (with radiographs of suspicious areas), and abdominal ultrasound (required only if bilirubin, alkaline phosphatase, or AST/ALT are elevated) Simultaneous bilateral breast carcinoma allowed Complete tumor resection on both breasts required Axillary dissection on both sides must meet criteria as above if both sides are clinically node-positive Axillary dissection on the second side optional if the axilla is clinically negative at the time of surgery and the other side is node-positive Adjuvant chemotherapy must begin within 14 weeks of initial pathologic diagnosis Hormone receptor status: Any receptor level allowed (values must be available if biochemical method used; immunocytochemical assay permitted)

PATIENT CHARACTERISTICS: Age: Not specified Sex: Female Menopausal status: Pre- or perimenopausal, i.e., meeting at least 1 of the following criteria: Normal menstruation Amenorrhea for less than 1 year (up to 3 years in patients under age 52) Biochemical evidence of ovarian function Hysterectomy without bilateral oophorectomy in patients under age 56 Premenopausal women no greater than age 50 who were started on replacement hormone therapy before amenorrhea are eligible Performance status: ECOG 0-2 prior to chemotherapy Hematopoietic: WBC at least 3,000/mm3 Polymorphs and bands at least 1,500/mm3 Platelet count at least 100,000/mm3 Hepatic: (unless abdominal ultrasound indicates liver metastasis) Alkaline phosphatase no greater than 2 times normal AST and/or ALT no greater than 2 times normal Renal: Not specified Other: No history of serious underlying medical illness or psychiatric or addictive disorder No second malignancy within 5 years except: Curatively treated nonmelanomatous skin cancer Curatively treated endometrium, colon, or thyroid cancer or carcinoma in situ of the cervix No plan for pregnancy during the 5-year study period Fertile women must use effective contraception (other than oral contraception) Accessible for treatment and follow-up

PRIOR CONCURRENT THERAPY: Biologic therapy: Colony-stimulating factors allowed (use must be documented) Chemotherapy: No prior chemotherapy No concurrent other cytotoxic therapy Endocrine therapy: Adjuvant tamoxifen (20 mg po daily) allowed up to 2 weeks before or during adjuvant chemotherapy provided drug is discontinued at randomization No long-term prednisone or other hormones Radiotherapy: See Disease Characteristics Surgery: See Disease Characteristics